elasticsearch 2.4.1 support

New:

• elasticsearch 2.4.1 support
• Union & Minus support read here
• _id on return (csv as parameters _id=true and site on show options )
• #157 routings support

Enhancements:

• #243 query optimization - use filter context when not ordering by score
• #295 Added support to negative coordinates on spatial queries
• #292 include and exclude support on top hits aggregation

Bugs:

• #187 csv format with multiple chars seperator
• #231 csv format with null on field value